轮机英语（二三管轮）Lesson 21 Fresh Water Generator.ppt

Unit2AuxiliaryMachineryLesson21FreshWaterGeneratorNewWordsandExpressionslaundry[?l??ndri]n.洗衣店；洗衣房dearth[d??θ]n.缺乏；不足evaporator[??v?p?re?t?]n蒸发器；汽化器cylindrical[s??l?ndr?kl]a.圆柱形的；圆筒状的demister[?di??m?st?(r)]n.除雾器，除雾剂brine[bra?n]n.盐水vacuum[?v?kju?m]n.真空；真空状态Celsius[?selsi?s]n.摄氏NewWordsandExpressionsparticle[?pɑ?t?kl]n.颗粒；微粒salinometer[,s?l?n?m?t?]n.盐量计distillate[?d?st?l?t]n.馏出物，蒸馏液vent[vent]n.(空气、液体的)出口purge[p??d?]v.清除，清洗throttle[?θr?tl]n.节流阀；节流杆；风门shallow[???l??]a.浅的；肤浅的osmosis[?z?m??s?s]n.渗透NewWordsandExpressionsmembrane[?membre?n]n.膜；薄膜dilute[da??lu?t]v.稀释；冲淡synthetic[s?n?θet?k]a.人造的；合成的Freshwaterisofdireneedonaship.Itisusedforvariouspurposessuchasdrinking,forpreparingfood,inlaundryservicesandinmanyotherdaytodayactivities.Inthepast,peopleusedtocarrytonsandtonsoffreshwaterinbarrelsorinspeciallymadetanks.Thiswasbecausetherewerenoothersourcesoffreshwateroncetheshipwasinsea,exceptrain,whichwasquiteunpredictable.Todayinspiteofmeansonboardtogeneratefreshwater,shipscarrytonsandtonsoffreshwaterinsegregatedfreshwatertanks.Buttherearemanyotherprocessesinwhichfreshwaterisusedandasgenerallythefreshwatertanksprovidedarenotsufficient,theneedarisestogeneratefreshwateronboard.Freshwaterisalwaysindearthalsobecauseitisverydifficulttokeepacheckonthewaterusagebythecrewmembersandalsotheusagecannotbeavoidableaswateriscontinuouslyrequiredonboardship(淡水总是缺乏，因为对船员的用水情况进行检查很难，同时船上不可避免的需要连续用水).Fig.21-1FreshwatergeneratorFreshwaterisgeneratedonshipbyafreshwatergenerator(FWG)showninFig.21-1,alsoknownasevaporator.Theprocessbywhichfreshwaterisgeneratedisknownasdistillationprocess.Seawaterisconvertedintofreshwaterbyevaporatingandcondensingtheseawater.Evaporationoftheseawaterise